Releasable door fastening



May 22, 1956 J. J. SCHAMOTTA RELEASEABLE DOOR FASTENING Filed March 2, 1953 INVENTOR'.

Schamotta,

ATTO Ills 5 United States Patent RELEASABLE DOOR FASTENING Jacobus 'J. Schamotta, Parktown North, Johannesburg,

Union of South Africa, assignor to Imperial Cold lStorage and Supply Company Limited, Cape Town, Union off South Africa, a corporation of the Union of South A rica Application 'March 2, 1953, Serial No. 339,719

Claims priority, application Union of South Africa March 1, 1952 4 Claims. (Cl. 292-92) This invention relates to releasable door fastenings of the emergency-exit ,type which, having been secured :on the outside of the door, may be released by persons accidentally locked in. Such fastenings are for example used on doors of cold storage rooms.

Known fastening devices of the kind mentioned depend on the undoing of a wing nut on the inside of the door. As the nut is seldom used, a person with numbed fingers and possibly in a panic will have great difficulty in releasing the nut.

An object of the invention is to provide a fastening which can be quickly and easily operated from the inside to unlock the door. A further object of the invention is to provide a fastening which when being released will also act to open the door to some extent to overcome wedging of the door.

A door fastening according to the invention comprises a latch formation adapted to be installed on a door, a keeper formation adapted to be installed on a door post, the latch formation and the keeper formation being arranged to interengage to secure the door on the outside of the door when the keeper formation is held down on the door post, a threaded bush on the keeper formation, a complementarily threaded head, a shaft carrying the threaded head and adapted to pass through the door post and means to turn the shaft on the inside of the door post, the threading being arranged that on turning of the shaft the keeper formation is forced from the door post and out of engagement with the head.

An embodiment of the invention is described hereunder and illustrated in the accompanying drawings, in which:

Figure l is a section through the embodiment in the secured position;

Figure 2 is a view similar to Figure l with the fastening in the unsecured position;

Figure 3 is a section on the line 6--6 of Figure 1 and Figure 4 is an elevation of a rack and pawl mechanism secured on the inside of a door post.

In the embodiment illustrated in Figures 1 to 4 the door 27 is of the conventional wedge type, i. e. the door 27 wedges in the door frame as illustrated next to the door post 28.

An arm 29 secured to the door 27 has a forked end 30 which carries a wing nut 31 which constitutes a latch formation. The nut 31 engages with a hinged bolt 32 in the conventional manner, the bolt being the keeper formation. The base 33 on which the bolt 32 hinges is formed as a thrust block with an internal quick screw threating 34. As shown in Figure 3 the block 33 is keyed against rotation by means of two keys 35 fixed to the post 28.

A shaft 39 passes through the post 28. At the outer end 36 the shaft carries a threaded head 37, the threading on which is complemental to the threading 34. At the inner end 38 the shaft 39 is secured to a lever 40 ice which has a spring pressed pawl 41 and a rack 42 secured to the door post 28. The rack includes a series of in dentations 43 into which the pawl enters under the action of its spring when the lever is moved and which prevent movement of the lever under the action of gravity alone.

As the threading 34 is at 45 degrees, it will be seen that by turning the lever 40 through degrees from the position shown in Figure 1 to the position shown in Figure 2 the head 37 rotates and thus forces the block 33 away from the door post 28. The door securing means will be released and the door forced open by one and the same action. Thus if a person is trapped inside the door 27 and the door becomes stuck for example by being iced up, the trapped person will be able to release the door fastening and to unwedge the door, simply by turning the lever 40.

While one embodiment of this invention has been shown and'described, it will be apparent that numerous modifications and variations thereof may be made without departing from the underlying principles of the invention. It is therefore desired by the following claims to include within the scope of the invention all such variations and modifications by which substantially the results of this invention may be obtained through the use of substantially the same or equivalent means.

I claim:

1. A releasable door fastening of the emergency exit type comprising a latch formation adapted to be installed on a door, a keeper formation adapted to be installed on a door post, the latch formation and the keeper formation being arranged to interengage to secure the door on the outside of the door when the keeper formation is held down on the door post, a threaded bush on the keeper formation, a complementarily threaded head, a shaft carrying the threaded head and adapted to pass through the door post and means to turn the shaft on the inside of the door post, the threading being arranged that on turning of the shaft the keeper formation is forced from the door post and out of engagement with the head, and the latch and keeper being adapted so to interengage that during displacement of the keeper the latch is displaced to move the door outwardly from the door post.

2. A releasable door fastening of the emergency exit type comprising a latch formation adapted to be installed on a door, a keeper formation adapted to be installed on a door post, the latch formation and the keeper formation being arranged to interengage to secure the door on the outside of the door when the keeper formation is held down on the door post, a quick threaded bush on the keeper formation, a complementarily quick threaded head, the bush and head being adapted to interengage, a shaft carrying the threaded head and adapted to pass through the door post and means to turn the shaft on the inside of the door post including a lever adapted to be secured to the shaft, a spring pressed pawl associated with the lever and a rack mechanism adapted to be secured to the door post, the pawl and rack being adapted to engage each other to secure the lever in any desired position on the rack, the quick thread being arranged that on turning of the shaft the keeper formation is forced from the door post and out of engagement with the head, and the latch and keeper adapted so to interengage that during displacement of the keeper the latch is displaced to move the door outwardly from the door post.

3. A releasable door fastening of the emergency exit type comprising a latch formation adapted to be installed on a door, a keeper formation adapted to be installed on a door post, the latch formation and the keeper formation being arranged to interengage to secure the door on the outside of the door when the keeper forma- 3 tion is held down on the door post, a threaded bush on the keeper formation, a complementarily threaded head, a shaft carrying the threaded head and adapted to pass through the door post and means to turn the shaft on the inside of the door post including a lever adapted to be secured to the shaft, a spring pressed pawl associated with the lever and a rack mechanism adapted to be secured to the door post, the pawl and rack mechanism being adapted to engage each other to secure the lever in any desired position on the rack, the threaded head and bush being arranged for interengagement so that on turning of the shaft the keeper formation is forced from the door post and out of engagement with the head, and the latch and keeper being adapted so to interengage that during displacement of the keeper the latch is displaced to move the door outwardly from the door post.

4. A releasable door fastening of the emergency exit type comprising a latch formation adapted to be installed on a door, a keeper formation adapted to be installed on a door post, the latch formation and the keeper formation being arranged to interengage to secure the door on the outside of the door when the keeper formation is held down on the door post, the keeper being adapted to be releasably secured to a shaft arranged to pass through the door post and means to turn the shaft on the inside of the door post, the connection between keeper and shaft being such that when the shaft is turned the keeper is forced from the door post and out of engagement with the shaft, and the latch and keeper being adapted so to interengage that during displacement of the keeper the latch is displaced to move the door outwardly from the door post.

References Cited in the file of this patent UNITED STATES PATENTS 381,740 Wollensak Apr. 24, 1888 1,615,300 Cantrell Jan. 25, 1927 1,919,501 Colvin July 25, 1933 2,461,426 King Feb. 8, 1949 2,473,205 Jazwieck June 14, 1949 2,636,767 Groeger Apr. 28, 1953 

